Known in the prior art are aircraft wheel and brake assemblies including a non-rotatable wheel support, a wheel mounted to the wheel support for rotation, and a brake disk stack having front and rear axial ends and alternating rotor and stator disks mounted with respect to the wheel support and wheel for relative axial movement. Each rotor disk is coupled to the wheel for rotation therewith and each stator disk is coupled to the wheel support against rotation. A back plate is located at the rear end of the disk pack and a brake head is located at the front end. The brake head houses a plurality of actuators that extend to compress the brake disk stack against the back plate. Torque is taken out by the stator disks through a static torque tube or the like.
To control operation of each brake assembly, a brake system control unit (BSCU) is typically employed, wherein the BSCU is operatively coupled to each brake assembly. The BSCU typically includes a microprocessor that executes a control algorithm which, based on a target brake pressure, commands the actuators to apply a force such that the actual brake pressure equals the target brake pressure.
The BSCU also implements anti-skid braking control. As is known in the art, anti-skid braking control detects, via wheel speed sensors or the like, when one or more wheels are in a skid condition. The BSCU will modulate a brake command signal provided to the brake corresponding to the skidding wheel, thereby bringing the wheel out of the skid.
Hydraulic braking systems generally are controlled using a pressure feedback scheme. For example, a target pressure signal (e.g., from a brake pedal) is provided to the BSCU, and the BSCU, via a servo valve or the like, controls the hydraulic pressure supplied to the brake actuators to satisfy the target pressure signal. Electric braking systems operate in a manner similar to hydraulic braking systems, but instead of regulating hydraulic pressure, a force applied by the actuators is regulated. The applied force may be directly measured by force sensors, or implied from position sensors (e.g., from a position of the actuator). The applied force or actuator position then may be equated to a pressure applied by the brakes.
In both hydraulic and electric brake configurations, the target brake pressure reference is derived from a brake pedal. More particularly, the brake pedal provides a target brake pressure reference to the BSCU, wherein brake pedal deflection is proportional to the target brake pressure reference.